1. Field of the Invention
The present invention is related to wireless tracking systems and methods. More specifically, the present invention relates to a wireless tracking system and method for a tag subject to extreme temperatures.
2. Description of the Related Art
The ability to quickly determine the location of objects located within a facility is becoming a necessity of life. To the uninformed observer, the placement of transponders, also known as tags, on numerous non-stationary objects whether in an office or home would appear to be an unnecessary use of resources. However, the uninformed observer fails to appreciate the complexity of modern life and the desire for efficiency, whether at the office or home.
For example, in a typical hospital there are numerous shifts of employees utilizing the same equipment. When a new shift arrives the ability to quickly locate medical equipment not only results in a more efficient use of resources, but also can result in averting a medical emergency. Thus, the tracking of medical equipment in a hospital is becoming a standard practice.
The tracking of objects in other facilities is rapidly becoming a means of achieving greater efficiency. A typical radio frequency identification system includes at least multiple tagged objects, each of which transmits a signal, multiple receivers for receiving the transmissions from the tagged objects, and a processing means for analyzing the transmissions to determine the locations of the tagged objects within a predetermined environment.
Medical equipment subject to extreme temperatures includes surgical kits or surgical trays which are typically sterilized in an autoclave at high temperatures to destroy any living organisms (bacteria, fungi, viruses and spores). Autoclaves generally use heat and high pressure to destroy the living organisms. These high temperatures are often in excess of 120 degrees Fahrenheit, and as high as 300 degrees Fahrenheit.
The surgical trays are typically composed of stainless steel, aluminum or another metal. Various surgical instruments are contained within the surgical tray. An example of such a tray is disclosed in Wood, U.S. Pat. No. 6,827,913, for a Modular Sterilization Tray Systems For Medical Instruments.
The autoclave sterilization temperatures are far beyond the typically room temperature operating ranges for most RFID tags or similar wireless tracking tags. However, there is a need to track the location of the surgical trays since the ability to monitor the location and the sterilization status of such surgical trays allows a hospital or other like facility to adequately prepare for a surgery procedure.
Nycz, et al., U.S. Pat. No. 7,118,029, for a Smart Instrument Tray RFID Reader, discloses the use of passive RFID tags that are attached to surgical instruments to provide information on the contents of a surgical tray. The RFID tags can be encased in such materials as Phenol, Glass, Wood, Epoxy resin, Silicon, Rubber, Polyvinyl Chloride, Acrylonitrile Butadiene Styrene, common plastic and Styrofoam.
Nicholson, et al., U.S. Pat. No. 6,255,949, for a High Temperature RFID Tag, discloses an RFID tag that is capable of withstanding temperatures of −40 degrees Celsius to 300 degrees Celsius. The tag is placed within a housing composed of a high thermally resistant material such as RYTON PPS compound or TEFLON.
Although the prior art has provided numerous solutions, the prior art has failed to recognize the problems associated with wireless location asset tracking in a sterilization environment.